In the past, an image-forming device has been known for forming a toner image in an electronic photo format using toner on an image support body, transferring this toner image directly or indirectly to paper and forming an image by fixing this transferred toner image to the paper using a fixing device.
This kind of image fixing device comprises for example multiple internal devices such as a paper supply unit, an image-forming unit, a transfer belt unit, a fixing unit and/or the like. Among these, in the fixing process, being the final process in image formation, various schemes are implemented in the fixing device in order to prevent negative effects from being applied to the formed image.
For example, there are cases in which flaws could occur, such as toner adhered to the fixing separator growing in a ribbon shape in a direction parallel to the direction of surface movement of the fixing belt that is a fixation nip former, becoming a large lump and having a negative effect on image quality.
In order to prevent this kind of flaw, Unexamined Japanese Patent Application Kokai Publication No. 2007-140189 proposes a fixing device provided with a separation claw in which is formed a groove extending in a direction orthogonal to the surface movement direction of the fixing belt and on a fixing belt contact position downstream side facing plane facing the surface of the surface movement direction downstream side of the fixing belt more than the position of contact with the fixing belt.
However, in the fixing process in this fixing device, there is a problem that toner adheres to the fixing belt in the surface movement direction, as well as the problem that when the separation claw is provided in a rib shape in order to minimize contact with the image-forming plane, a linear separation guide mark remains on the formed image plane.
The device disclosed in Unexamined Japanese Patent Application Kokai Publication No. 2007-140189 prevents toner adhered in the surface movement direction of the fixing belt from growing in a belt shape by a groove being formed on the back surface of the separation claw, but is not related to the front surface structure of the separation claw and thus does not give consideration to resolving the problem of separation guide marks remaining on the formed image.
In addition, besides the above-described problems, in the fixing process in this fixing device, there is the problem that water that the printing medium has absorbed at room temperature becomes water vapor and evaporates when heat is added, and this water vapor adheres to the sheet metal with which the ribs and/or the like of the separation guide are assembled and becomes water droplets, and these water droplets adhere to the printing medium and have a negative effect on the quality of the formed image.
In consideration of the foregoing, it is an objective of the present invention to provide a fixing device that prevents the occurrence of separation guide marks on the formed image of the printing medium at the time of fixing and that also prevents the occurrence of image flaws by water droplets caused by water vapor generated from the printing medium.